Inhibitory effects of D2 agonists by striatal injection on excessive release of dopamine and hyperactivity induced by Bay K 8644 in rats.

We investigated by means of behavioral and neurochemical studies the effects of either D(1) or D(2) agonist on excessive dopamine release and hyperactivity induced by the microinjection of Bay K 8644, and an L-type Ca(2+) channel stimulant, into the rat caudate putamen under a novel environmental condition. Hyperactivity (locomotor activity and rearing counts) and significant increases in extracellular dopamine levels induced by Bay K 8644 were concomitantly observed. D(1) agonist, SKF81297, administered into the caudate putamen did not block Bay K 8644-induced hyperactivity measured by monitoring both animal activity and increases in extracellular dopamine levels detected by microdialysis. Pretreatment with the D(2) agonists, bromocriptine, talipexole and pramipexole, into the caudate putamen significantly blocked Bay K 8644-induced hyperactivity for 45 min after Bay K 8644 administration, although the single administration of these agonists significantly potentiated locomotor activity and rearing behavior. Furthermore, these agonists significantly suppressed Bay K 8644-induced extracellular dopamine levels. Our results indicate that these D(2) agonists (1) act on postsynaptic neuronal D(2) receptors under conditions of normal or low dopamine release in the caudate putamen, and (2) act on presynaptic D(2) receptors (autoreceptors) when excessive levels of dopamine are released or hyperdopamine neuronal activity is induced. Consequently, the effect of D(2) agonists in the clinical treatment of Parkinson's disease may be due to stimulation of postsynaptic D(2) receptors rather than presynaptic autoreceptors.

Assessing systemic 11beta-hydroxysteroid dehydrogenase with serum cortisone/cortisol ratios in healthy subjects and patients with diabetes mellitus and chronic renal failure.

11beta-hydroxysteroid dehydrogenase (11beta-HSD), an enzyme regulating mineralocorticoid like action of glucocorticoid, oxidizes active cortisol to inactive cortisone. Impaired activity of this enzyme is associated with apparent mineralocorticoid excess (AME) syndrome and is characterized by hypertension and hypokalemia. Recent investigations suggest the presence of hypertensive subjects with low activity of 11beta-HSD. The blood concentration ratio of cortisone/cortisol reflects the overall conversion of cortisol to cortisone and may be an index to assess the systemic activity of 11beta-HSD. We evaluated the peripheral blood concentration ratio of cortisone/cortisol as a possible marker to identify subjects with hypertension thought to represent impaired 11beta-HSD activity. We compared this ratio in healthy subjects and patients with diabetes mellitus (DM) or chronic renal failure (CRF). Peripheral blood samples were collected from 69 healthy subjects, 44 DM, and 36 CRF patients in the morning (9:00 to 11:00 AM). Twenty-six DM patients (59%) and 32 CRF patients (89%) met the criteria for having hypertension. Serum cortisol and cortisone concentrations were determined by high performance liquid chromatography (HPLC). All values for serum cortisone and cortisol levels were within the normal range. Serum cortisone/cortisol ratio in the healthy subjects was distributed with a range of 0.113 to 0.494 (median, 0.243). Compared with healthy subjects, DM and CRF patients had significantly low (P <.01) serum cortisone/cortisol levels (median, 0.188 [range, 0.092 to 0.313] in DM and 0.088 [range, 0.031 to 0.140] in CRF). Bimodal distribution of cortisone/cortisol, found in DM patients with hypertension, represented high- and low-ratio groups around the border of the ratio 0.2. Kidney function, DM duration, and complications varied between the high- and low-ratio groups. The low ratio group (<0.2), whose 11beta-HSD activity was considered low, had an increase in blood urea nitrogen (BUN) levels and experienced nephropathy, neuropathy, retinopathy, and prolonged DM duration when compared with the group with a ratio greater than 0.2. The data suggest that the serum cortisone/cortisol ratio reflects the change in 11beta-HSD activity and is dependent kidney function. This is a possible marker to evaluate glucocorticoid excess hypertension observed in DM and CRF patients.

Thirty cases of bronchial asthma associated with exposure to pet hamsters.

BACKGROUND: The identification, isolation, and elimination of allergen(s) causing bronchial asthma are the most efficient form of treatment. The pet industry has diversified recently, increasing the risk of exposure of pet owners to many unknown antigens. We clinically studied the characteristics of asthma associated with exposure to pet hamsters. METHODS: The study group comprised 30 adults in whom the onset, recurrence, or exacerbation of asthma was triggered by contact with pet hamsters. Clinical characteristics such as sex, age, period required for symptom onset, species of hamster, treatment and disease course, smoking status, and hamster-specific IgE antibodies in serum were studied. RESULTS: The male: female ratio of the study group was 1:1.3, and mean age was 37.7 years. Patients with no previous history of asthma initially presented with cough, progressing to episodes of asthma. Asthmatic symptoms were associated with hamster contact and ranged in severity from mild to severe. Three patients required hospital admission for treatment. The mean period from the start of hamster exposure to the onset of asthmatic episodes was 15.7 months. Dwarf hamsters were responsible for most cases. The CAP-RAST score for hamster-specific IgE antibodies was 1 to 4 in 22 patients and 0 in 8 patients. Eight patients with a score of 1 or higher for hamster-specific IgE antibodies had a CAP-RAST score of 0 for mite antigen. In these patients, terminating hamster contact resulted in a rapid improvement in symptoms, with no need for further treatment. Twenty-three of the 30 subjects (76.7%) were smokers. CONCLUSION: Exposure to pet hamsters is an important risk factor for the onset, recurrence, or exacerbation of asthma. Smoking may also increase the risk of asthmatic symptoms in patients exposed to hamsters.

Clinical evaluation of response to long-term treatment with Pranlukast in patients with bronchial asthma.

BACKGROUND: Short-term treatment with pranlukast, a leukotriene receptor antagonist, has shown to be effective for the management of asthma. The effectiveness and safety of long-term treatment with pranlukast remains to be established. OBJECTIVES: The aim of this study was to determine the effects of pranlukast on morning peak expiratory flow rates (PEFRs), the diurnal variation of these values, and disease severity. METHODS: Fifteen men with bronchial asthma were studied for 5 years. During the first year, the subjects were treated with a bronchodilator; some also received inhaled and oral corticosteroids. During the next 4 years, the subjects received pranlukast in addition. RESULTS: Mean PEFR increased after the start of treatment with pranlukast. The increase in PEFR occurred later in subjects with more severe disease. Diurnal variation of PEFR was unchanged, but subsequently decreased. The condition of all subjects improved, but the greatest improvement was obtained in patients with mild to moderate asthma. CONCLUSIONS: Long-term treatment with pranlukast is effective for the management of bronchial asthma, particularly in patients with mild to moderate disease. Our results suggest that the effectiveness of antiasthmatic drugs should be evaluated over a period of years, rather than on a short-term basis.

A novel 11 beta-hydroxysteroid dehydrogenase inhibitor contained in saiboku-to, a herbal remedy for steroid-dependent bronchial asthma.

To identify the inhibitor of prednisolone metabolism contained in Saiboku-To, we conducted in-vitro experiments of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), using rat liver homogenate and cortisol as a typical substrate. We studied the effects of ten herbal constituents on 11 beta-HSD. Five herbal extracts showed inhibitory activity with Glycyrrhiza glabra > Perillae frutescens > Zizyphus vulgaris > Magnolia officinalis > Scutellaria baicalensis. This suggests that unknown 11 beta-HSD inhibitors are contained in four herbs other than G. glabra which contains a known inhibitor, glycyrrhizin (and glycyrrhetinic acid). Seven chemical constituents which have been identified as the major urinary products of Saiboku-To in healthy and asthmatic subjects were studied; magnolol derived from M. officinalis showed the most potent inhibition of the enzyme (IC50, 1.8 x 10(-4) M). Although this activity was less than that of glycyrrhizin, the inhibition mechanism (non-competitive) was different from a known competitive mechanism. These results suggest that magnolol might contribute to the inhibitory effects of Saiboku-To on prednisolone metabolism through inhibition of 11 beta-HSD.

Impact of free magnolol excretions in asthmatic patients who responded well to saiboku-to, a Chinese herbal medicine.

Saiboku-To, a mixture of ten different herbal extracts, has been used in Japan and Czechoslovakia for corticosteroid-dependent severe asthma to reduce the maintenance doses of corticosteroid. Magnolol has been considered to be an active component of Saiboku-To as an inhibitor of 11 beta-hydroxysteroid dehydrogenase and T-lymphocyte proliferation resulting in corticosteroid-sparing. To investigate the relationship between magnolol and the clinical effects of Saiboku-To, urinary magnolol excretion was compared in responders and non-responders under long-term Saiboku-To treatment. The clinical outcome of the Saiboku-To treatment was evaluated in nine asthmatic patients at 52 weeks after the onset of the treatment, using individual fluctuation of asthmatic points obtained from the patients' diary cards. Three patients whose clinical conditions were improved by the treatment were termed responders and six others were termed non-responders. The difference in the amounts of the total magnolol excreted were not significant; however, free (or non-conjugated) amounts of magnolol excreted in the responders were 7 times those in the non-responders (P < 0.05). These results suggest that the magnolol might be responsible for the therapeutic effect of Saiboku-To, indicating practical bioavailability in the responders.

Liquid chromatographic determination of magnolol in urine collected from volunteers after a single dose of saiboku-to, an oriental herbal medicine for bronchial asthma.

Saiboku-To is an anti-asthmatic herbal remedy which consists of ten herbal extracts. To investigate the clinical relationship between the effects and chemical components of Saiboku-To, a simple and sensitive high-performance liquid chromatographic method (HPLC) for determination of magnolol, one of the major urinary products, was developed. Organic solvent extraction of urinary magnolol was conducted by diatomaceous earth column rapid-flow fractionation using ethanol/dichloromethane (8/92, v/v). Recovery rates of magnolol were more than 99% with coefficient of variations less than 6% in the concentration range 9.7-970 ng mL-1. Subsequent HPLC determination of magnolol was achieved using a conventional silica-gel column, a mobile phase mixture of acetic acid/diethyl ether/n-hexane (0.2/17.0/82.8, v/v), and a UV-absorption detector set at 290 nm. Calibration was on the basis of peak height ratio between magnolol and flavone as an internal standard. The method was used to demonstrate excretion profiles of magnolol in healthy and asthmatic subjects following single administration of Saiboku-To.

Different effects of traditional Chinese medicines containing similar herbal constituents on prednisolone pharmacokinetics.

Three major traditional Chinese medicines (TCM), Sho-saiko-To, Saiboku-To, and Sairei-To, consist of similar herbal prescriptions containing glycyrrhizin, which is a strong inhibitor of 11 beta-hydroxysteroid dehydrogenase. We performed cross-over open trials in healthy subjects to clarify prednisolone pharmacokinetics on co-administration of these preparations. All subjects received a single oral dose of 10 mg prednisolone before oral treatment with one of the test preparations. After a 2-week wash-out interval, they received one of the test preparations for three days at daily doses of 7.5 or 9.0 g. On the third study day, 10mg prednisolone was administered orally in combination with the test preparation. Area under the curves (AUC) of prednisolone before and after the treatment decreased from 0.94 to 0.78 mg h L-1 (P < 0.05) in the Sho-saiko-To group, increased from 0.92 to 1.06 mg h L-1 (P < 0.01) in the Saiboku-To group, and did not change in the Sairei-To group. AUC ratios of prednisone and prednisolone, which reflect the 11 beta-hydroxysteroid dehydrogenase activity, increased in the Sho-saiko-To group (P < 0.01), decreased in the Saiboku-To group (P < 0.01), and did not change in the Sairei-To group after the treatments. Similar results were observed in ratios of endogenous cortisone to cortisol. Because of the equal glycyrrhizin content in all three preparations, it was unexpected that the 11 beta-hydroxysteroid dehydrogenase effect was different amongst the three groups. These observations suggest that some unknown metabolic enzyme modifiers, promoters or inhibitors, may be involved in these traditional treatments.

Effects of absorbed components of saiboku-to on the release of leukotrienes from polymorphonuclear leukocytes of patients with bronchial asthma.

Previous studies confirmed the efficacy of the Chinese herbal remedy Saiboku-to in patients with steroid-dependent asthma. We studied 8 phenolic compounds, isolated from the urine of patients receiving Saiboku-to, with respect to their effects on leukotriene (LT) release by polymorphonuclear leukocytes (PMN) obtained from 6 patients with atopic asthma and 8 healthy subjects. The compounds (0.01-10 micrograms/ml) were incubated with Ca2+ ionophore (A23187)-stimulated PMN, and concentrations of leukotriene B4 (LTB4) and leukotriene C4 (LTC4) in the supernatant were measured by EIA. Each compound suppressed the release of LTB4 and LTC4 by PMN obtained from healthy and asthmatic subjects. In particular, baicalein and magnolol were 5-10 times more potent than azelastine, an antiallergic drug, and significantly suppressed LTC4 release by PMN obtained from asthmatic patients, as compared with healthy subjects. Suppression of LTC4 release by these compounds may play an important role in the clinical efficacy of Saiboku-to.

A study of factors contributing to bakers' allergy symptoms.

It has been known for many years that bakers, who work in an atmosphere filled with wheat flour and other grain products, often suffer from bronchial asthma and other allergy symptoms. We examined 36 cooks (males: 33, females: 3, average age: 29.1 years) exposed to wheat products while baking bread or making confectionaries in a hotel. Their clinical symptoms were investigated, and peripheral blood eosinophils, serum IgE, wheat flour specific IgE, IgG1, IgG4, and antibodies to alpha-amylase and papain were measured. Clinical symptoms were present in some cases, the most common being rhinitis (13), itching and skin eruptions (8), ocular symptoms, including tearing, itching and conjunctival injection (8), and respiratory symptoms, including cough and sputum production (8). Wheat flour specific RAST was positive in 44.4% of cases. Peripheral eosinophils and wheat flour specific IgG1 levels were increased in those with positive RAST scores. Total IgE level and wheat flour specific IgG4 also seemed to be increased in those with positive RAST scores. Wheat flour specific IgG1 and IgG4 seemed to correlate positively with wheat flour specific IgE. The exposure duration correlated with neither total IgE nor wheat flour specific IgE. In those who were wheat flour RAST positive, wheat flour specific IgG1 levels correlated negatively with exposure duration. In RAST negative cases, however, there was no correlation. Similarly, there seemed to be a tendency for wheat flour specific IgG4 levels and exposure duration to correlate negatively in RAST positive cases. The subjects of this study initially worked in poorly ventilated areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnolol from Magnolia officinalis inhibits 11beta-hydroxysteroid dehydrogenase without increases of corticosterone and thymocyte apoptosis in mice.

Magnolol is an 11beta-hydroxysteroid dehydrogenase (11beta-HSD) inhibitor contained in Magnolia officinalis which is used in Chinese remedies. We have reported that glycyrrhetinic acid, a strong 11beta-HSD inhibitor isolated from licorice, induces apoptosis of murine thymocytes via accumulation of corticosterone. In this paper, we report that magnolol inhibited 11beta-HSD without increases in the blood concentration of corticosterone and in thymocyte apoptosis in mice. Oxidative activities of the enzyme (from corticosterone to 11-dehydrocorticosterone) in liver, kidney and thymus in vitro were examined 24 h after a single administration of magnolol. Magnolol inhibited the enzyme activity in kidney (P < 0.0001) and thymus (P < 0.002), while the activity in liver was not affected. Blood concentrations of corticosterone in the magnolol-treated mice were unexpectedly lower than those in the control animals (P < 0.002). This means that the inhibition of 11beta-HSD by magnolol did not increase the systemic level of corticosterone which is relevant to thymocyte apoptosis. Accordingly, our flow cytometric analysis of thymocytes after magnolol treatment showed no change in the number of apoptotic cells. We concluded that unlike glycyrrhetinic acid, magnolol selectively inhibited 11beta-HSD in kidney and thymus but not in liver, so that the blood concentrations of corticosterone could not exceed the control level.

A strategy for discovering biologically active compounds with high probability in traditional Chinese herb remedies: an application of saiboku-to in bronchial asthma.

A novel strategy for discovering biologically active components in traditional Chinese herb remedies was performed from a pharmacokinetic view. The hypothesis was that the active compounds should appear in blood and urine with appropriate blood concentrations and urinary excretion rates after the administration of herbal-extract mixtures. In this research, we applied our procedures to Saiboku-To, one of the most popular Chinese herbal medicines in Japan. Consisting of 10 different plant extracts, it is used for the treatment of bronchial asthma. The analytical method adopted was a rapid-flow fractionation (RFF) for extraction-fractionation of lipophilic components in urine followed by silica-gel high-performance liquid chromatography (HPLC) equipped with a multichannel ultraviolet (uv) absorption detector. beta-D-Glucuronidase-treated urine samples collected before and after the administration of Saiboku-To to healthy and asthmatic subjects were treated with the RFF apparatus to afford three pH-dependent fractions: strongly acidic (S), weakly acidic (W), and neutral (N). HPLC of these fractions, monitored by the multichannel uv detector, showed three new peaks in the postadministrative urine: one in the N fraction, two in the W fraction, and none in the S fraction. A compound in the N fraction was identified with authentic magnolol, a major component in Magnolia officinalis. Two compounds in the W fraction were identified by comparison with authentic samples as 8,9-dihydroxydihydromagnolol and liquiritigenin, metabolites previously isolated from M. officinalis and Glycyrrhiza glabra, respectively.

Systematic analysis of post-administrative saiboku-to urine by liquid chromatography to determine pharmacokinetics of traditional Chinese medicine.

To disclose the mystery of a traditional Chinese medicine and to identify biologically active components, we analysed post-administrative urine for Saiboku-To, an anti-asthmatic Chinese herbal remedy. Systematic analysis of the components appearing in the urine was carried out by high-performance liquid chromatography (HPLC) with normal- and reversed-phase modes in combination. beta-D-glucuronidase-treated urine was subjected to rapid-flow fractionation (RFF) to achieve fractional extraction of lipophilic components with exhaustive recovery rates. The extracts were analysed by HPLC equipped with a multi-channel UV-detector. In the first stage of HPLC, we conducted a normal-phase mode run to find magnolol derived from Magnolia officinalis, as the most hydrophobic component showing minimum retention time among the urinary products of Saiboku-To. In the next stage, mobile phase solvent composition for reversed-phase HPLC was optimized so as to retain magnolol up to 60 min. Under these conditions, other Saiboku-To urinary products, which were more polar than magnolol, appeared within 60 min. Our HPLC method used marker compounds like magnolol and could indicate the terminal peak position on the reversed-phase chromatography. We found a total of eight components in the post-administrative Saiboku-To urine. Structure identification of the isolated pure materials was achieved using nuclear magnetic resonance (NMR)-, mass (MS)- and UV-spectra, and HPLC retention profiles. They were magnolol and 8,9-dihydroxydihydromagnolol stemming from M. officinalis, medicarpin and liquiritigenin from Glycyrrhiza glabra, baicalein, wogonin, and oroxylin A from Scutellaria baicalensis, and davidigenin of an unknown origin. The pharmacological mystery of Saiboku-To should be disclosed by resolving the pharmacokinetics and pharmacodynamics of these urinary products independently and synergistically.

Effects of cardiac contraction and coronary sinus pressure elevation on collateral circulation.

Controlled coronary sinus occlusion was shown to retard necrosis of ischemic myocardium. To elucidate this mechanism, regional myocardial blood flow measurement was performed with and without coronary sinus pressure elevation to 30 mmHg (CS30). Colored microspheres were injected into left and right coronary arteries after coronary perfusion of the left anterior descending (LAD) coronary artery was stopped in seven isolated canine hearts with induced atrioventricular block, either paced at 120 beats/min by direct right ventricular stimulation [beating heart (B)] or during asystole induced by stopping pacing [nonbeating heart (NB)]. Regional myocardial blood flow in the LAD perfused area in the control state in the NB with normal coronary sinus pressure (NB-CScont; 0.27 +/- 0.13 ml.min-1.g-1, means +/- SE) was significantly greater than those in B-CScont (0.19 +/- 0.09 ml.min-1.g-1; P < 0.05) and in NB with CS30 (NB-CS30; 0.19 +/- 0.09 ml.min-1.g-1; P < 0.05). Regional myocardial blood flow of the LAD area in B with CS30 (B-CS30; 0.23 +/- 0.10 ml.min-1.g-1) was significantly greater in comparison with that at B-CScont and NB-CS30 (P < 0.05). The augmentative effect of the LAD area regional myocardial blood flow was observed only in the periphery of the ischemic region but not in its center. Cardiac contraction and CS30 impede regional myocardial blood flow in the ischemic bed independently. The coexistence of these two factors enhances regional myocardial blood flow. In conclusion, coronary sinus pressure elevation in B may participate in augmenting collateral flow.

Inhibitory effects of lignans and flavonoids in saiboku-to, a herbal medicine for bronchial asthma, on the release of leukotrienes from human polymorphonuclear leukocytes.

To identify the anti-allergic components contained in Saiboku-To, a herbal medicine for the treatment of bronchial asthma, we studied the effects of eight phenolic compounds, which have been identified as the major human metabolites of Saiboku-To, and three triterpenoids contained in Saiboku-To on the release of leukotriene (LT) from human polymorphonuclear leukocytes (PMLs) stimulated with Ca(2+)-ionophore A23,187. All phenolic compounds exhibited dose-dependent suppression on release of both LTB4 and LTC4, while triterpenoids did not show any effects, except for glycyrrhetinic acid, which selectively inhibited LTC4-release. The five phenolic compounds, magnolol, dihydroxydihydromagnolol, baicalein, medicarpine and davidigenin, were found to exert a marked inhibition on LTB4- and LTC4-release with IC50 values of 0.7-15.3 microM. The results suggest that the phenolic compounds contribute to the anti-allergic effects of Saiboku-To through suppression of LT-release from PMLs.

Individual variations in lymphocyte-responses to glucocorticoids in patients with bronchial asthma: comparison of potencies for five glucocorticoids.

Glucocorticoids (GCs) are known to be effective for bronchial asthma, however, a considerable number of asthma patients fail to respond to GC despite the onset of serious side effects. Here we examined individual sensitivities to five clinically-used GCs in 40 asthma patients and 100 healthy subjects. Peripheral-blood mononuclear cells (PBMCs) were isolated from these subjects, and their in vitro sensitivities to hydrocortisone, prednisolone, methylprednisolone, dexamethasone, and betamethasone were determined with a mitogen-assay procedure. The number of PBMCs positive to IL-2 receptors (IL-2Rs) as well as soluble IL-2R (sIL-2R) levels in serum were concomitantly measured in asthma patients, and relationships between these cytokine indices and PBMC-sensitivities to GCs were also examined. Large individual variations in GC IC50s have been observed in PBMCs from asthma subjects, especially in prednisolone IC50s (ranged from 1 to 10,000 ng/ml). When compared with healthy subjects, asthma patients tend to show PBMC-resistance to prednisolone (p < 0.05). Moreover, potencies of methylprednisolone on PBMC-blastogenesis were > 10 times higher than those of prednisolone in both healthy subjects and asthmatics (p < 0.01). In asthma patients, IC50s of hydrocortisone, prednisolone and betamethasone against PBMC-blastogenesis were significantly correlated with elevated percentages of IL-2R-positive PBMCs (p < 0.05), while the IC50 of methylprednisolone showed no such correlation. sIL-2R levels did not correlate with IC50s of any of the GCs examined. Thus, the results showed that a part of asthma patients exhibited PBMC-resistance to GCs, especially to prednisolone. Methylprednisolone potency was unexpectedly higher (> 10 times) than prednisolone potency. Our results also raised the possibility that PBMC-resistance to prednisolone in asthma may correlate with an increase in IL-2R positive PBMCs.